The Classical Greek letter for the discriminant is 'Delta' , which is shaped like a triangle with the left side being a vetrtical line and standing on a corner of the triangle.
However, 'D' or 'd' is often used in maths.
Some authors use delta for the discriminant but most people nowadays use D or d.
There are no weird letters in maths. Greek mathematicians were responsible for a significant amount of the early mathematical work and they, naturally used Greek letters. Many of these letters are still used today. Just because you are not familiar with characters in the Greek alphabet does not make them "weird letters".
In ordinary everyday letters . . . pi In Greek letters . . . Π
pis
There are no books called "letters" (or epistles) in the Hebrew Old Testament. All books that are designated as "letters" are Greek, and found in the New Testament.
Athena
There are 24 letters in the Greek Alphabet
This is it in Greek letters, not the actual word: Δεστινυ
Greek letters are letters, they dont mean anything out of context.
The Russian alphabet consists of 33 letters, while the Greek alphabet has 24 letters.
adventure = ΠΕΡΙΠΕΤΕΙΑ (Pronounced "peripetia")
24 letters.
ανάπτυξης
Katharizo
from the greek words alpha and beta, the first 2 letters of the greek alphabet.
The two Greek letters that begin with P and have three letters are PHI and PSI. There are no Greek letters that end with S.
Ελληνικό χαρτοφυλάκιο
26 letters